linux-kernel - Re: [PATCH 0/3] net: renesas: rswitch: R-Car S4 add HW offloading for layer 2 switching

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <27047e61-8307-472d-96dd-1e5b89dc427f@lunn.ch>
Date: Fri, 4 Jul 2025 19:53:08 +0200
From: Andrew Lunn <andrew@...n.ch>
To: Nikita Yushchenko <nikita.yoush@...entembedded.com>
Cc: Michael Dege <michael.dege@...esas.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
	Niklas Söderlund <niklas.soderlund@...natech.se>,
	Paul Barker <paul@...rker.dev>, Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] net: renesas: rswitch: R-Car S4 add HW offloading
 for layer 2 switching

On Fri, Jul 04, 2025 at 11:05:14AM +0200, Nikita Yushchenko wrote:
> > Looking at the code, it is not clear to me what would happen with:
> > 
> > ip link add name br0 type bridge
> > ip link set dev tsn0 master br0
> > ip link set dev br0 up
> > ip link set dev tsn0 up
> > ip link add name br1 type bridge
> > ip link set dev tsn1 master br1
> > ip link set dev br1 up
> > ip link set dev tsn1 up
> 
> Per design, it shall enable hardware forwarding when two ports are in the same brdev.

So in this case, the hardware offload has been reserved by br0, but is
in fact never used, since there is only one port in the bridge. If i
was to then do

ip link set dev tsn2 master br1
ip link set dev tsn2 up

br1 would not be offloaded, but done in software.

	Andrew